The role of the ICT sector in the people daily life is causing a significant growth of the power consumed by the network equipment. In this context, transparent WDM networks represent a promising solution for reducing the power consumption of telecom networks. For this reason transparent WDM networks attract a lot of interest and several power-aware routing and wavelength assignment algorithms are available in the literature. These approaches, however, seem to consider power minimization as the only parameter to be optimized. Little or no attention is given to other important network aspects, e.g., connection requests blocking.